Start trying now. Every monthly cycle, you should be dropping a load in her daily over about a 8 day stretch to cover when she should be ovulating on paper as well as to help cover any real life fluctuations in her cycle window. Sperm can survive much longer in the uterus, so you can take a day off here or there, but never go 2 days in a row during that stretch without a creampie if you are playing seriously to win - it’s going to be work off testosterone now, and you will probably want to order some tadalafil and take that with some P5P daily over that window. The average couple takes about 6 months to conceive (and that’s just a statistical average), so even if you do this all correct you are looking essentially at playing Russian Roulette just to meet average. We nailed it on our second month, but it could just as likely have been 10 months.
You can do this during a restart attempt/off gear, but you can also stay on test and blast HCG. Also blasting HMG and even Proviron can help raise fertility in that scenario.
A sperm/fertility test will tell you if you are fertile right now. If you aren’t, it depends on how much you want to wait. It’s different for everyone.