okay so for (1) we need to find the points where the velocity is 0. So first we need to find an expression for velocity, velocity is the rate of change of displacement, or in other words ds/dt. Once you have found this, you can set it to 0 to find the times where the velocity is 0. Have you got any working so far which you could post?
(2) part b is similar to the above, except you want times where acceleration is 0. remember that acceleration is the rate of change of velocity, so dv/dt.
Sketching graphs:
If you follow these steps for sketching graphs it shouldn't matter what type of function you have.
1) Find the x and y intercepts, if any exist.
2) Find any stationary points of the curve, determine their location and their nature (max/min etc)
3) Determine the behaviour of the curve towards +/- infinity, and find any asymptotes of the curve (if any).
Have a go at sketching it and if you get stuck i can help.