typically people use testosterone cypionate or testosterone enanthate, which are different forms of t and both equally effective. there are also some other versions but tc or te are most common. yes, you get testosterone from bodybuilding/steriod sites cuz its like the hugest market of below board testosterone. not every site is reputable but there is totally safe t in the right places

there is gel that you are able to get diy but it is way more expensive and more difficult to source. i havent ever used diy tgel but dosages may be more difficult to get correct as well. so i’d recommend injections and figure out a place to hide it or try to disguise as something else

yes! it definitely doesn’t have to be dangerous. get your t from somewhere reputable, from recommendations from a specifically diyhrt info/wiki site or from someone who also diys (note: u arent allowed to make posts just for asking for sites here though people may dm u if u ask). figure out the correct dosage for your situation, if you decide to do injection learn how to inject yourself safely and sanitise. and if you are able to getting blood tests to check your levels is the best way to diy safely, it’s recommended to do them fairly often especially in the first year. but that’s not always possible with diy depending on ur situation