If you're just doing pedal you'll have to pull up on the seat a little, not very hard, to keep the cranks level. And you only need a couple inches rolling hop if you can find a low enough ledge, just high enough where your tire doesn't drag when you're in a stall.

Nice, I understood everything, I only left one question, if I do the grind only with the pedal, I have to pull it behind the other pedal right? If I did not pull back the pedal cranks were not horizontally and they will soon fall and be at 12 o'clock and there will not be a good thing hahahahah
Thanks a lot Julia , today i will improve my rolling hops and try to do a grind on my city skate park , The only problem is the rolling hop , i can´t hop high or far :/ i really ned to pratice that .

Yeah, I'm doing a grind in that picture. Personally I grind on only my pedal cause I think it feels better, but on a ledge like the one in my picture you can do both crank and pedal if you like. I think it was easier to learn with crank and pedal. You just have to be careful when you start grinding on rails to do only pedal, or the crank can easily slip and your unicycle will get stuck. You need to keep standing after you hop on the ledge, and lean over the foot you're grinding with. The key to grinding is the lean, make sure you're fully committing and leaning over whatever you're grinding on to go down the full length and slide of the edge. Hope that helps! Feel free to ask me if you need any more tips.

Hi julia , can i make you 4 litlle questions?haha
in Your profile pic you are doing a grind right?
you grind with your crank and pedal? or just with the pedal?
To land a grind I need to stand on the pedals, or I could sit on the seat after the rolling hop?