Probably here, but I see you also appear to have a registration on TenForums...
Macrium has a lot of options, including scheduling, Differential images, backup set image retention rules (and even more if you pay for it, Incremental imaging for a start). I understand why it can be confusing trying to jump straight in. But it can be really simple to use if you just ignore all the optional extras.
For the simplest possible guide, ignore all the confusing options and just install Macrium on the machine you want to image. Then open Macrium and select 'Create an image of the partition(s) required to backup and restore Windows'.
Click Next, untick all the retention rules. Don't bother with scheduling. When you get to Finish it says: Backup and Save Options.
Untick 'Run this backup now' (unless you actually want to make the image straight away). The 'save Backup Definitions...' option will save your chosen backup settings, which can be run manually any time you want (as a Full backup or a Differential) from Macrium's 'Backup Definitions Files' tab.
A Differential image contains just the changes since the last Full image, so can be much smaller. For a restore you just need to keep the latest Full image (and it's latest Differential, if you made one).
You can safely ignore all the retention rules and delete old images manually as required. Retention rules are only really of use if you automate the whole process with scheduling, but that too is something you can safely ignore. I make all my images manually from my backup definitions files at a time of my choosing.