You can start
here, Del.
If you click the 'help' toggle on your left upper screen that may help you out as well. Ya know, I've never clicked that toggle to date. So, at best it's just a guess.
If you see or read a post that generally applies to the guidelines Susan's laid out in that Rep Rules link then click on the green arrow by the person's avatar and fill out the reason screen that pops up (you have a limited amt of characters for that so keep it brief.)
Or, if you find a post that violates the site rules or is inflammatory or something of the kind that just invites a fight you may click the red arrow under the avatar to give negative rep point. I presume that has the same reason box that pops up. (Never used that either to date.)
You can also appeal any negative rep, or I suppose positive rep, you don't feel you deserve to the admins by clicking the lil toggle that appears in the lower left of the "Reputation Modification Notification" that you'll receive when someone ups or negates your rep. Again there will be a pop-up to fill out if you do that. That pop-up has rather more space to write your objections.
Hope that gives you some idea. I think things like automatic 10 for new members and automatic 25 for staff members have been discontinued for the most part.
Hope this helps.
Nichole