Please advise how to get ready for giyur and brit. What clothes to wear. Etc details. If am so happy can I give out food to jews in the street for zdaka is it ok? Or invite the jews in uman in the street to a restaurant?

Congratulations on your upcoming giyur and brit- I really respect those who chose Judaism out of free-will, objective judgement and intellectual honesty! You can celebrate any way you wish, and surely giving tzedaka, and celebrating with your new brothers is a good way. Some people sponsor a Kiddush in the local shul. I suggest asking the local Beit Din what you should wear and how you will feel afterwards, for there also is the recuperation period. All the best, and welcome to the Chosen People!