Sadly, I do not know of any such text. I'm not that much into yoga to know of any such text that would be trust worthy, and Tantra is so vast that it is even hard to give a general overview of it. There is one book I found recently and that is S.C. Banerji - Companion to Tantra, which gives the descriptions and differences between various tantrik currents, but it is a purely scholar work. Almost all of the reliable material on Tantra is scholarly work, so that leads me to my second point.
>I'm trying to get out of the armchair, please assist
Then this might not be the best way for you. Let me explain - Tantra and various yogas, which are instruments in Tantra, are all very practical and straight to the point, but they require you to have some knowledge already as to the modes of working and the general metaphysics of the system. Secondly, there is a lot of misinformation about these subjects, and when you are studying them it takes a lot to sort through the misinformed sources and find the real ones. The original and not distorted teachings are usually only found in scholarly works on the subject which are pretty heavy to read, especially for a beginner as there is a lot of Sanskrit terminology involved. So, while walking this path is practical and the path is extremely powerful in itself, you must do a lot of scholarly work too, in the beginning especially.
Now, there is no one book on Tantra or on Yoga that would sufficiently explain everything. There is no crystallized structure to them, there is no "general" Tantra. All you have is various schools, all slightly differing from one another when it comes to workings and metaphysical theory behind it. Furthermore, there is no Guru to guide us (well, apart from "Guru within" meme) so for a Western student of these systems it is necessary to study a lot of texts, to get to know the system from as many sources as possible, to forge our own understanding of it.
A good entry level book in my opinion is Kali Kaula by Jan Fries (simply because it was my entry-level book) and while it does mention other Tantrik schools, it is concerned primarily with Kalikula - a Shakta branch concerned with Kali as the deity presiding over this path.
shivashakti.com has a great wealth of information in regards to Shaktism and Kaula, the books by Mike Magee do too. Material from Woodroffe is okay, although it is written in such a manner that I find them quite boring most of the time and hard to follow.
I was asked about materials on Kashmir Shaivism recently
Here is something I wrote regarding "tantric sex" meme and a bit about Tantra in general
And then you have Buddhist Tantra which is also quite distinct from Hindu one, except for the fact that it is too not a homogeneous tradition (you have Vajrayana, The Southern Treasure school of Bon etc).
Here is something that should get you started on chakras, other articles on this blog are sometimes useful too
If you want to get out of armchair then just start doing stuff. No matter what you do, meditate, get into lucid dreaming, do some fun shamanic journeying etc. Find something you are already familiar with, something you can do or something that is pretty fast and easy to learn and just do it. In the meantime study different traditions to find the one you like the most and extract the teachings and implement them into your own work. It's not binary - either you just study or either you just practice. I think that combining the two works best - practice what you study or study more about what you practice. At least that's what I'm doing.
So… I'd rather you not study Tantra at all, if it would just turn into an excuse of not doing practical shit.
I'd really wish to be more helpful, but as I said before - most of my knowledge of yoga comes from various mentions scattered around different texts. Some practice here, some practice there etc. I really don't have any one book about this stuff that I would study and that would explain the stuff to me sufficiently. It's almost the same with Tantra in my case - studying wide array of texts and forging my understanding through it, being able to see the tradition from multitude of perspectives. I've read some hatha yoga manuals but I haven't practiced from them much, just did it on a general principle of broadening my knowledge.
On the second thought Prana and Pranayama book from Bihar yoga is nice, it has some faults but it explains pranayama way better than that meme """""Hindu-yogi"""" book from Atkinson, but it doesn't go into too much of the really occult practices of Tantra and is based solely on Upanishads from what I've gathered.