Writing to line 3 and 4 of an LCD

Hello all, I could use a bit of help on a 20x4 HD44780 LCD. I can put strings and characters onto line 1 & 2 but when I try to print to line 3 line 1 is overwritten. It seems there are really only 2 lines in a 4 line display. I tried shifting the cursor but was unsuccessful in that endeavor. I can’t seem to find any info on how write to the line 3 & 4. I Tried several different ways including writing only 20 characters on line 1 then 20 on line 2 but none of the attempts worked. Any ideas?...

Writing to line 3 and 4 of an LCD