Not to trivialize it, but the basic steps are:
1. Add a VPN host to your home network, either as another role on your router/firewall or as role on a host inside your network. For example, if you're running pfSense as your firewall, you can add an IPSec/L2TP or OpenVPN role to the pfSense host. Many hardware router/firewall devices have VPN host capabilities. You can start simple by defining users at the VPN host. Later you can use your home network's LDAP directory for users, but I personally didn't bother doing that.
2. Set up your laptop(s) and phone(s) to connect to that VPN. Disable "split tunneling" on the devices. If split tunneling is enabled, only traffic that is intended for your private network would be sent to the VPN. Disabling it requires that all traffic—even traffic destined for the public Internet—needs to be routed through the VPN host.
3. Connect to the VPN whenever you are outside of your home.
4. You can optionally assign a static private IP to each device so that when you're connected, all devices use known IP addresses that you can name using a local DNS server. This would allow you to, for example, reach your laptop by the name "laptop.yourdomain.org" (or whatever). I give all of my devices hostnames so that I don't need to remember their IP addresses.
5. The result is you have a personal "virtual private network" that facilitates private LAN-like communication between all of your devices. For example, I use this to access my personal file server from anywhere.
6. You can get even more sophisticated by setting up site-to-site VPN connectivity between your home network and a machine or network you run at a data-center. This allows you to, for example, reach not just your home file server but also manage your personal public-facing Internet services running at your data-center hosted machine or VM—from any of your devices.