Is the gasket already attached to the bead. Normally you clip the bead in then push the gasket in after. Use soapy water and wedge a glazing packer between the bead and glass as you go.
Never seen them like this either. One tilt and slide is bad enough but I bet the metal rod at the bottom has come out of the socket, it's only held in with a small grub screw
Show us a pic of the house. White plastic Windows are what they are. Don't look great on some properties but will keep the weather out. All depends what you want to pay. Like white Windows would not go in this house