By autoexposure do you mean the autolevels in RT??
There is a levels tool in DT and it has an auto button but in the scene-referred workflow your goal is to set middle grey with exposure and not the boundries with something like autolevels… then when that anchor is set you use either sigmoid or filmic to map your tones on either side of that anchor…
As noted in @tankist02 reply you can use the picker and do an exposure that will at the start be based on the whole image using a 50% target value for lightness…this is often good and works okay with the tonemappers.
You can modify this by selecting your subject of interest or an element that should be middle grey and you will get an exposure calculation uses that target roi…
If you leave filmic and sigmoid off for the moment that often generates an image that has what appear to be blown highlights…don’t worry… its nailing your midtones that is the key in the modern workflow of DT…
Finally the exposure module does have an automatic setting that also doesn’t do a bad job in most cases out of the gate…
Taking the image from here…
Default scene referred with Sigmoid…
Using the picker on the whole image…too bright in this case as the image is dark
Selecting instead the plane as the subject… not too bad…
Finally using auto exposure mode instead
