You can show a fixation cross during a specified interval within a trial

Column name: fixation

Possible values:

ISI (fixation cross appears on screens between stimuli during a sequential presentation)
ITI (fixation cross displayed before the start of the trial during the ITI)
withStim (fixation cross will appear on top of the stimuli only)
allTrial (fixation cross appears throughout the trial, on all screens - between and after stimuli as well)
allStim (fixation cross appears throughout the trial, on all screens until presentation of stimuli is finished)

Customisation options

In addition to placement options, you can also change the size of the fixation cross by setting:

Pixel height → e.g. 450 displays the cross at a maximum height of 450px
Relative scaling → e.g. 150% enlarges the cross to 150% of its default size

Other visual content in trial