Basic DHCP server help

Is there a way to edit a DHCP rule to change the pool size without deleting it and starting over

How do you set DHCP reservations? Is it the same as in a consumer router where you hit make static and leave it where it is or do I need to move it outside the pool?

Thanks in advance.

For change the DHCP-range size go to IP / pool
Double click on DHCP-pool1 and change the size.

For make a static IP go to DHCP-server you select the ip-address ore MAC and click on set static