Frontside (F/S) Boardslide can feel a bit intimidating compared to the backside, since you are sliding with your back facing forward. The key is to twist your upper body so it stays parallel to the rail as you slide. Once you are comfortable with the backside boardslide, give this one a try.
STEP BY STEP TIPS
1. Approach to the rail straightly.

Approach the rail at a sharp angle, almost parallel, with your ollie stance. If you go too slow, you might get stuck on the rail, so having a decent amount of speed actually makes it safer.
2.Keep body parallel to the rail.

The entry is the key. As mentioned above, twist your upper body slightly so it stays parallel to the rail, then pop a gentle 90° ollie to ease the board onto the rail. At first, try entering near the end of the rail so that even if you get stuck partway, you can still roll out and practice safely.
3. Stay right above the rail.

To slide properly, focus on maintaining the same form you used at entry. Keep your weight centered—avoid leaning too far forward or backward, and stay directly above the board. To exit, simply turn the nose forward, and you should naturally come out of the slide. It is best to practice on a low, short rail.