Echoing what Leafstamp has said, assuming that OP is wanting a march about sex based rights, that a good starting point would be to contact the various groups whose focus this is and ask if they would be interested in taking part.
Stressing that it is meant to be a cooperative event that would help show the number of organisations (including LGB?) campaigning on this issue. Lots of opportunity for placards and banners.
The idea being to show how many people (some men would want to come???) are actively concerned about what is happening. ie women's rights being erased by prioritising trans rights eg EA etc.. (re men marching, I have a vague memory of a Turkish Women's groups who always came to IWD marches with men - not because they needed escorts but because in Turkey IWD has always been mixed) and they always marched at the back.
If existing groups are on board, they each have mailings / sm followings so info about the event could be spead more easily.
And some of us on FWR on virtual feminist groups could think about even if it is only one neighbour or work colleague then could work with to share info about the event locally and make shared travel arrangements.
And taking a chance on good weather if it was held in the summer the march could end up in a park and we could have a huge picnic, no need for macho spray painting etc.. And a chance for FWRers to show their dedication to cakes, whether making them or eating them!
Dogs and children welcome?!
We could have ballons as well. Purple, green, white ...