To merge two features together select the first feature, click on the merge tool from the top menu or right click and select the merge tool, then click on the second feature.

To merge more than two features together hold down the shift key and select all of the features that you want to merge, click on the merge tool from the top menu or right click and select the merge tool.

You can also select features of the same type. To do this simply right click on the feature that you want to select-all. In the tool bar that appears then click 'Select feature type', click on the merge tool from the top menu or right click and select the merge tool.

To bulk select all features, click the 3 vertical dots next to the plan name, then click 'Select all':

A pop-up will then appear that gives you the option to select all or all of a certain feature type. Please note you cannot merge a feature such as an area and a line together.

Now click on the merge tool from the top menu or right click and select the merge tool.