how do i restart ipad without home button

It is a common misconception that an iPad (or iPhone) can remain fully functional with damaged or defective physical buttons. 

Whilst Accessibility features (such as assistive touch) can be used to augment the User Interface, these features cannot be used as a substitute for physical button sequences that must be used to trigger system recovery actions. Sooner or later, as now, you will encounter a situation from which you cannot recover.

If the iPad has shut-down (i.e., has fully powered off), connecting the iPad to it Power Adapter will cause the iPad to restart.

Until repaired, you will not be able to resolve a locked-out (disabled) iPad - or reset a forgotten device passcode. To arrange repair, you may consider arranging repair through the Genius Bar at your local Apple Store or Apple Authorised Service Provider (AASP):

Genius Bar Reservation and Apple Support Options - Apple

Alternatively, you can use Apple’s mail-in repair service:

iPad Repair & Service

ahdoa wrote:

my home button is broken but still functional

??? As in it is broken but not broken? ;-)

Click on this link for information about 'iPad Service and Repair' --> iPad Repair & Service - Apple Support

Use the “Get an Estimate” tool to review potential costs if you get service directly from Apple.