Hi,
You don't need any guide, just install openvpn package.
Put your .ovpn config files in /etc/openvpn
cd /etc/openvpn
Then run it manually as follows:
MLD> openvpn *.ovpn
Thu Mar 3 16:35:09 2022 OpenVPN 2.4.0 arm-unknown-linux-gnueabihf [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [PKCS11] [MH/PKTINFO] [AEAD] built on Oct 14 2018
Thu Mar 3 16:35:09 2022 library versions: OpenSSL 1.0.2n 7 Dec 2017, LZO 2.10
Thu Mar 3 16:35:09 2022 WARNING: No server certificate verification method has been enabled. See http://openvpn.net/howto.html#mitm for more info.
Thu Mar 3 16:35:09 2022 TCP/UDP: Preserving recently used remote address: [AF_INET]--:25000
Thu Mar 3 16:35:09 2022 Socket Buffers: R=[180224->180224] S=[180224->180224]
Thu Mar 3 16:35:09 2022 UDP link local: (not bound)
Thu Mar 3 16:35:09 2022 UDP link remote: [AF_INET]--:25000
Thu Mar 3 16:35:13 2022 TLS: Initial packet from [AF_INET]--:25000, sid=48ad5f99 43227113
Thu Mar 3 16:35:14 2022 Control Channel: TLSv1.2, cipher TLSv1/SSLv3 ECDHE-RSA-AES256-GCM-SHA384, 1024 bit RSA
Thu Mar 3 16:35:14 2022 Peer Connection Initiated with [AF_INET]--:25000
Thu Mar 3 16:35:15 2022 SENT CONTROL : 'PUSH_REQUEST' (status=1)
Thu Mar 3 16:35:15 2022 PUSH: Received control message: 'PUSH_REPLY,redirect-gateway def1,dhcp-option DNS --,dhcp-option DNS --,route 10.10.0.1,topology net30,ping 5,ping-restart 30,ifconfig 10.10.0.246 10.10.0.245,peer-id 5,cipher AES-256-GCM'
Thu Mar 3 16:35:15 2022 OPTIONS IMPORT: timers and/or timeouts modified
Thu Mar 3 16:35:15 2022 OPTIONS IMPORT: --ifconfig/up options modified
Thu Mar 3 16:35:15 2022 OPTIONS IMPORT: route options modified
Thu Mar 3 16:35:15 2022 OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified
Thu Mar 3 16:35:15 2022 OPTIONS IMPORT: peer-id set
Thu Mar 3 16:35:15 2022 OPTIONS IMPORT: adjusting link_mtu to 1625
Thu Mar 3 16:35:15 2022 OPTIONS IMPORT: data channel crypto options modified
Thu Mar 3 16:35:15 2022 Data Channel Encrypt: Cipher 'AES-256-GCM' initialized with 256 bit key
Thu Mar 3 16:35:15 2022 Data Channel Decrypt: Cipher 'AES-256-GCM' initialized with 256 bit key
Thu Mar 3 16:35:15 2022 ROUTE_GATEWAY 192.168.1.1/255.255.255.0 IFACE=eth0 HWADDR=
Thu Mar 3 16:35:15 2022 TUN/TAP device tun2 opened
Thu Mar 3 16:35:15 2022 TUN/TAP TX queue length set to 100
Thu Mar 3 16:35:15 2022 do_ifconfig, tt->did_ifconfig_ipv6_setup=0
Thu Mar 3 16:35:15 2022 /sbin/ip link set dev tun2 up mtu 1500
Thu Mar 3 16:35:15 2022 /sbin/ip addr add dev tun2 local 10.10.0.246 peer 10.10.0.245
Thu Mar 3 16:35:17 2022 /sbin/ip route add --/32 via 192.168.1.1
Thu Mar 3 16:35:17 2022 /sbin/ip route add 0.0.0.0/1 via 10.10.0.245
Thu Mar 3 16:35:17 2022 /sbin/ip route add 128.0.0.0/1 via 10.10.0.245
Thu Mar 3 16:35:17 2022 /sbin/ip route add 10.10.0.1/32 via 10.10.0.245
Thu Mar 3 16:35:17 2022 Initialization Sequence Completed
By the way, i noticed there is Webif setup in Network – VPN but i didn't try it
Edit: you can upload vpn config in Webif using Upload vpn config option.