@tecno there are multiple ways of doing it. M104, M140 and M141 set the hot end, bed and chamber temperatures respectively without waiting for them to reach temperature before proceeding to the next command. So they will all heat concurrently. Then you can use M116 to wait for them all to be reached:
M104 S225 ; set extruder temp
M140 S70 ; set bed temp
M141 S60 ; set chamber temp
M116 ; wait for all temps to be reached
Or if the hot end heats quickly but the bed and chamber heat slowly, you might want to do this instead:
M140 S70 ; set bed temp
M141 S60 ; set chamber temp
M116 ; wait for bed and chamber temperatures to be reached before heating the hot end
M104 S225 ; set extruder temp
M116 ; wait for all temps to be reached
You can substitute variables in [ ] for the actual values if the slicer supports that.
Using M104 followed by M109, or M140 followed by M190 is the old (Marlin) way of doing things.