On the app, select the mob you wish to mark, then simply click on the View Details button underneath the mob.
From here, head to the More button on the bottom right of the screen and then hit Mark.
If you have multiple mobs in this paddock, then you will be asked if you would like to mark all maternal mobs, or just the selected mob. If you choose to mark all maternal mobs, then a list of these mobs will display underneath.
If you wish to keep all lambs in the same Mob please select Create a single grouped mob. If you wish to separate lambs by sex, ensure that Create a single grouped mob is not selected. From here, just input the amounts of Marked lambs (for each sex if applicable).
The final step is to enter the marking details (for each seperate mob if separated by sex).