Stuffy Nose

I am a new user and I use the Resmed Airsense 10 with a full mask. I currently have a sinus infection. I find it harder to breath at times because of the congestion. Are there any recommendations? I have the heat and the humidifier on 6.

Lots of Simply Saline type of nasal spray all day long.
Oral meds to help reduce congestion....whatever works for you.
If a hot steamy shower helps...then maybe increase the humidifier setting and put a little more moisture in the air.
If worse comes to worse...something like a minimal amount of Afrin can be used short term to help out.

Now if this "sinus infection" started after starting cpap and you aren't ill with a real infection but instead just having nasal congestion then it could be cpap rhinitis from either too much humidity being used or not enough humidity being used.
When the nasal mucosa get unhappy with the moisture content of the air they can give us some pretty nasty symptoms that mimic a bad allergy attack or sinus infection.

Sometimes people say "sinus infection" and they are talking only about nasal mucosa stuff and not actual sinus stuff.

X-Lear Nasal Spray (available at Target) and X-Lear Max (Amazon) have helped me a lot. Nedi Pot may help (X-Lear packets available). Don't assume higher humidity will help, you should experiment. If it's a regular problem, you may need a full face mask for occasional use.