Add force to 3rd person character

I am currently developing a 3rd person character on unreal engine 4. I have an sliding animation which is played when I press the left shift. I would like that when I press the left shift ,my character to move forward continously until I release the button. I understand that there may be some way I could add force; or change the velocity in blueprint.
Does anybody know how to achieve this?
Thanks
Ps: Sorry for my english; I am a spanish native speaker.

If you you are using character movement , create a float variable, when you press shift set it to 1 and when it s unpressed set it to 0 , and then link this variable to scale value of “add movement input” all inside Tick function.