It might help you to lurk in the queer conception section for insemination tips.
For one thing, I wouldn't worry about your age. People much older than 38 bear children healthfully (did you see that someone in their 70s just had a baby a few weeks ago?!).
Self-insemination...are you meaning with frozen sperm or do you have a known donor?
I can't help with frozen sperm because I chose to go with fresh sperm from a friend. But I *can* help with that.
I did the insemination myself (well, with my partner) and we just bought the basic supplies...sterile cup, 5 cc needle-less syringe, gloves. It's a pretty self-explanatory thing and we erred on the cautious side and I stayed with my hips on a pillow for 15 minutes right afterward.
I'd recommend some herbs to help too so you can get the most for your money with the sperm.
Vitex, aka Chaste Berry, can be made into a tea and regulates cycles, calms cramps, and increases fertility. It is amazing and definitely my favorite TTC herb.
Maca--a root from Peru I believe. Used for many centuries and works well for increased fertility. Can cause an over-excited libido, be careful.
Ovulens--not an herb, but a device for tracking your cycles. Very handy. You basically spit on it and then look through the microscope to see where you are in your cycle and when you are ovulating. Also shows if you are pregnant.
Partnered mama with DD (01/04) and DD (08/09) and hoping to conceive and also adopt in 2017!