If you can reach down, hold your open lips apart, put the container so the entry to the urethra (in the area between your clit and the entry to your vagina - if you can get to check out where it is with a mirror it is helpful so you know exactly where it is) is in the middle of the container.

Other option is to use a funnel, which does get hard if you have to get a mid-stream flow.

If you want to be a bit more adventurous, then stand in the shower, with your foot up on a stool/chair and get the flow that way.

Urine is the most sterile liquid to come from the body, so don't worry about getting it on you.