I have 2 potty chairs.... one for upstairs and one for downstairs. When my kids were potty training, I just put it nearby wherever they were. I also left them naked on the bottom.
At this young age, per their Fine-Motor skills... they CANNOT yet, pull down or pull-up their own pants.... or underwear or whatever. So you do have to help them.
Or, just leave them naked on the bottoms.
It takes time. Going poop in a 'toilet' takes time... it is often the latter part of potty mastery. Normal.
ALSO, what we have and MANY of my friends have, is a car potty. I got it from Amazon. If you input the search word "on the go potty" many will come up. This is a LIFEsaver... when on the road, stuck in traffic, at parks or anywhere where there is no toilet nor clean ones. We to this day, STILL use ours, ever since my Daughter was 2 years old. She is now 8 years old.
I STRONGLY suggest getting one. YES!
all the best,
Susan