From command line, just type: acroread myfile.pdf.
To open pdf files directly from desktop manager, highlight any pdf file and right click, choose "Open with", then "Other". Now browse to where the command acroread is (it is /usr/bin/acroread), choose and check "Remember the application for this type of file". Click OK. This is same as you define files types on Windows machine.
To use acroread to open pdf files automatically from browser, do the
following:
On Mozilla, click Edit->Preferences. Then (click the + sign on navigator if
necessary) click Helper Applications. On the right side you will see there is
one defined aplication: xdvi for dvi files. To add an entry for pdf file, click
New type, put "Application/PDF" as MIME type, PDF file as "description" and "pdf"
as extension. If you choose "open with default application", then xpdf is used.
If you want to use acroread, choose open with command and browse to the location
/usr/bin/acroread. Click OK to save the setting.