Using Tools->Insert Instructions from File can let you insert instructions as mnemonic text from a file.
Below is an INIT instruction, of which I've also attached the screen shot. Some are ranged. Some are single initializations. Some are real, negative, positive values.
Note that the leading 3 in the INIT "3 ..." must NOT change. It tells the import how many parameters there are PER ROW (since ALL the rows are on a single line, in double quotes). If you have any questions about the pattern, just ask here.
// this first line is important - it tells the import which PLC this is targeting (change the part number to H2-DM1 or DM-SIM if necessary)
PLC H2-DM1E
STR ST1
INIT "3 V100 V109 42 D20 D33 -5 V110 ST1023 1 R22 ST1023 3.14 R100 R199 1.234"
// ST1023 for the END of RANGE is how Designer internally designate NO RANGE
Just insert those/your lines in your own .TXT file and use the Tools menu mentioned at the top. Make sure you are in EDIT MODE (Ctrl+E) And see the attached screen shot.