you can use shortcodes and add dashboard wizards to front end
But you need to include the js and css enque them.

Login and check if there is an option above the calender on overview take leave

if not
you can do some custom code modifications

For the employee role add in functions-capabilities.php

case erp_hr_get_employee_role():

add this line ‘erp_leave_create_request’ => true,

Deactivate and reactivate the plugin But before that
Change this lines
if ( $roles_hr ) {
foreach ($roles_hr as $key => $role) {
add_role( $key, $role[‘name’], $role[‘capabilities’] );
}
}
to

if ( $roles_hr ) {
foreach ($roles_hr as $key => $role) {
remove_role($key);
add_role( $key, $role[‘name’], $role[‘capabilities’] );
}
}

as add role will not modify the role
in class-install.php file