To create an Ascent plan, select the point you wish to ascend from (this needn't necessarily be the last point - you can ascend earlier if you like) press CTRL+A (or use the 'Ascent/Create' menu option).
Alternatively, CRTL+T, or 'Ascend/Track Back' Track Back creates a mirror of the current dive profile, with decompression stops inserted as they are needed. This is useful when Cave diving.
Use the Conservatism slider on the Preferences screen to add additional conservatism. This may be useful if the dive includes additional workload, takes place in cold water or you as a diver are additionally pre-disposed to getting DCS. Pushing the slider all the way to the right will pad decompression stops the most.
The 'PPO2 Max' control on the same screen allows you to select your maximum decompression PPO2 value for the total ascent, or just a portion. Most users will maintain a value of 1.6 (bar) but lower values may be advisable to stay within CNS clock limits.
You can change the default last stop depth using the 'Last Stop' dropdown. Options are 3m, 4m, 4.5m, 5m, 6m, (or 10ft, 12ft, 15ft, 18ft & 20ft in Imperial Units)
Selecting the Bail-Outs option will add information to the Slate plan regarding additional stop time required if any of the selected decompression gases became unavailable, or provide a bailout plan for a CCR dive should the unit malfunction.
The 'Range' option creates a range plan, which will provide alternative deco-stop times for the current profile ('Square Dives' only, we're afraid) if 'cut short'.
Having created an ascent, you can change points and edit gases as before. If, for instance, an ICD risk is shown, hover over the relevant point and make a note of the recommendation. Change the gas to suit, then recreate the ascent.
Once 'out of the water', you can create subsequent dives either by adding points manually, or using the 'Repeat Dive' function in the 'New Dive' dialog.
Similarly, Use CTRL+R (or Ascent/Range Plan) to view and print the Range Plan (if calculated).