Making lidded pies is tricky when using gluten free pastry since the dough is crumbly and doesn't have the elasticity and strength of a wheat pastry. You can try other options instead, such as a lattice top, or cut out shapes from the pastry and place them on top of the filling. A crumble topping is another option, made with gluten free flour, of course!
If you absolutely want to make a lidded pie with gluten free pastry, try this method: for the pastry case, place ball of dough in the centre of your dish or tin, cover with cling film, then press evenly with the bottom of a glass till the entire base is covered.
For the lid, use the 'extrusion method': roll the pastry between two sheets of lightly floured parchment. Transfer with the parchment to the fridge and chill for at least 2 hours before peeling off the parchment and covering your pie. If it breaks, don’t panic, just use water to glue the pastry back together.