Hi , It is an expression meaning " to be able to deal with it , to adapt to it ( it here is something ,situation etc),that is to say to overcome the difficulty of a situation or anything , to transcend the difficult phase of a certain situation and be able to deal with it in a smoother, more flexible mode .

It means to hurry up! For example if a child is too slow in eating their food, the mother may say, " Come on get on with it, eat your food before it gets cold.''