Open up gamemaker. Click open, and choose one of the tutorial games. Take the time to understand how it works. Repeat until you have learnt all of the example games. Now go to the help file, read anything you may need to know from that. Follow any tutorials it may contain. Now go to the tutorials and examples forum, choose a random tutorial and take the time to understand how it works, and read any documentation it contains. Repeat until you know how to make a River City Ransom Style Beat-em up, and have learnt how to ask specific questions.
When you are ready, you will know.
Ha your funny, but the fact is there's people that know how to and could teach someone with less experience instead of be a jerk and waste their time
This will take you out of the slope and put you on its surface right away, not too high and not too low. it's a simple and easy way to make sure the guy walks up the slopes, but he can still have his gravity and all of that too.
make sure precise collision checking is on with the slope's sprite, too.