Dgraph-alpha fails on ubuntu (Installscript with system.d)

curl https://get.dgraph.io -sSf | bash

this is my install command in ubuntu server, i didn’t use

-s -- --systemd

and after i successfully install the dgraph.
i type the command dgraph version, and i can get info of dgraph version. is it means i had already successfully install the whole dgraph things i need in ubuntu ?
and when i type the command dgraph alpha , i got many code showing on the screen that the ubuntu console , like this

Charset=function(e,t){if(!e||!t)return e;var n=r.parse(e);return n.parameters.charset=t,r.format(n)}},8706:(e,t,n)=>{"use strict";var i=n(5158)("express:view"),a=n(5622),r=n(5747),o=a.dirname,s=a.basename,c=a.extname,p=a.join,l=a.resolve;function u(e,t){var a=t||{};if(this.defaultEngine=a.defaultEngE0519 11:04:35.715363 2910132 run.go:543] Lambda server at port: 20000 stopped with error: exit status 1
E0519 11:04:36.110545 2910132 groups.go:1223] Error during SubscribeForUpdates for prefix "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x15dgraph.graphql.schema\x00": Unable to find any servers for group: 1. closer err: <nil>
E0519 11:04:36.218751 2910132 pool.go:311] CONN: Unable to connect with localhost:5080 : rpc error: code = Unavailable desc = connection error: desc = "transport: Error while dialing dial tcp [::1]:5080: connect: connection refused"
E0519 11:04:37.111646 2910132 groups.go:1223] Error 

do i mistake somthing ? or whta do i need to do to solve the problem ? thank for any help !