Task: Manage Slack channel and users automatically

n8n workflow JSON:
{"id":"164","name":"Create a channel, invite users to the channel, post a message, and upload a file","nodes":[{"name":"On clicking 'execute'","type":"n8n-nodes-base.manualTrigger","position":[250,250],"parameters":{},"typeVersion":1},{"name":"Slack","type":"n8n-nodes-base.slack","position":[450,250],"parameters":{"resource":"channel","channelId":"n8n-docs","additionalFields":{}},"credentials":{"slackApi":"Slack Bot Access Token"},"typeVersion":1},{"name":"Slack1","type":"n8n-nodes-base.slack","position":[650,250],"parameters":{"userIds":["U01797FGD6J"],"resource":"channel","channelId":"={{$node[\"Slack\"].json[\"id\"]}}","operation":"invite"},"credentials":{"slackApi":"Slack Bot Access Token"},"typeVersion":1},{"name":"HTTP Request","type":"n8n-nodes-base.httpRequest","position":[1050,250],"parameters":{"url":"https://n8n.io/n8n-logo.png","options":{},"responseFormat":"file"},"typeVersion":1},{"name":"Slack2","type":"n8n-nodes-base.slack","position":[850,250],"parameters":{"text":"Welcome to the channel!","as_user":true,"channel":"={{$node[\"Slack\"].json[\"id\"]}}","attachments":[{"title":"Logo","image_url":"https://n8n.io/n8n-logo.png"}],"otherOptions":{}},"credentials":{"slackApi":"Slack Bot Access Token"},"typeVersion":1},{"name":"Slack3","type":"n8n-nodes-base.slack","position":[1250,250],"parameters":{"options":{"channelIds":["C01FZ3TJR5L"]},"resource":"file","binaryData":true},"credentials":{"slackApi":"Slack Bot Access Token"},"typeVersion":1}],"active":false,"settings":{},"connections":{"Slack":{"main":[[{"node":"Slack1","type":"main","index":0}]]},"Slack1":{"main":[[{"node":"Slack2","type":"main","index":0}]]},"Slack2":{"main":[[{"node":"HTTP Request","type":"main","index":0}]]},"HTTP Request":{"main":[[{"node":"Slack3","type":"main","index":0}]]},"On clicking 'execute'":{"main":[[{"node":"Slack","type":"main","index":0}]]}}}