I recommend you to train mainly with dumbbells to increase your muscles (weight).

First of all, I want to buy a book to practice bodybuilding with dumbbells. Such books are sold online and in bookstores.

Then there are cushions and stools. I think the mat should be two meters long and one meter six wide. You can buy it if you have money. You can buy it cheaply if you have no money. Better buy a carpet. You can't buy leather cushions. This is too thin; It is best to adjust the stool to a full angle, so that the upper, middle and lower parts can be practiced well when practicing the chest; Another important thing is dumbbells. You should buy an assembled dumbbell with adjustable weight.

As for the venue, it can be fixed or indefinite. Just use a ventilated place at home.

You still have to buy books first, and then buy other matching ones. After reading the book, feel it, see if you can do it, and then buy other items.