I just switched mid-cycle from Test Enanthate to T-400 and took my first shot yesterday. Not bad, wasn't as painful as people said.
Your question is a little scary because of the way it's worded. Doesn't sound like you've done much planning or research.
Read the sticky at the top of the postings, there's a ton of info. If you're a beginner around 180 lbs., rough guess, I'd say go with 1/2 cc (200mg) twice per week (400 mg/wk) to start.
I like to workout about an hour after my injection, but it really doesn't matter at all. The Test is long-acting, meaning that it doesn't reach its peak in your bloodstream for several days. In fact you may not see effects for several weeks.
Do some more reading bro, especially the stickies at the top of the postings page. It's cool that you're asking questions. Keep looking and asking. PM me if you want and I'll help you with what I know.