Audacity does not have a bars/beats option for the timeline, though there is a feature request for this:
Let the Timeline display the detected time signature and bars (12 votes)
I can add your vote for this feature if you like.
Given this limitation, I wrote a plug-in that can create a label track with labels marking the bars and beats.
See here for information about labels and label tracks: http://manual.audacityteam.org/man/Label_Tracks
The plug-in is available here: https://forum.audacityteam.org/t/beat-per-minute-labels/20785/1
To install the plug-in, put it in the Audacity plug-ins folder, then restart Audacity. The “BPM Labels” generator will appear in the Generate menu.
Audacity 1.3.x is required (recommended version is 1.3.14 http://audacityteam.org/download/)
I would welcome any feedback about the plug-in. Please post comments about the plug-in in the BPM Labels topic.