So far the guys have given great advice. I'll try to add to that. Use 4wd which will improve the ability of the tractor to push into the material. The FEL is not a bull dozer blade. By that I mean fill the FEL with dirt then move it to the dump area unless it is very close. When pushing dirt resistance builds up fast and the tractor loses traction - starts spinning the tires.
How to load up the FEL. Just prior to pushing into the material shift to low range and 4wd at about 1500 - 1600 rpms or maybe a little less until you get some practice. As the tractor pushes into the material lift the bucket and curl it back toward you. You might try this action with an empty bucket a few times to get the hang of it. On my tractor I pull the joystick back toward me and to the left at the same time. If the bucket is full it may not raise or curl. Just tap the reverse pedal a time or two to ease out of the dirt.
As best you can try to load the same amount of dirt all across the bucket. Too much dirt on one side or the other may make the tractor feel tippy. That is why you want
ballast. The 58" tiller should work well - just be mindful that it is back there.
Now you have a full bucket, go fill a hole, come back do it again.
On the right hand side of the bucket you will see some metal about two inches wide. That represents the angle of your bucket. Tilted up toward you means your are not digging. Flat means you are skimming across the ground. Tilted away from you means you are digging.
By lunch tomorrow you will be a pro.
PS: sorry if some of this is repeat ....