You should explore code samples in
https://github.com/microsoft/BotBuilder-Samples/tree/main/samples
rather than trying to understand how to use the SDK through the class references.
sendOperationRequest & sendRequest aren't really meant to be used explicitly, ConnectorClient uses it to send the request.
In order to send your message you first need a conversation reference (otherwise, how would the bot know which conversation to send the message to?) For example, look at the sample code on the documentation page of the NPM package you linked :
var { ConnectorClient, MicrosoftAppCredentials } = require('botframework-connector');
async function connectToSlack() {
var credentials = new MicrosoftAppCredentials('<your-app-id>', '<your-app-password>');
var botId = '<bot-id>';
var recipientId = '<user-id>';
var client = new ConnectorClient(credentials, { baseUri: 'https://slack.botframework.com' });
var conversationResponse = await client.conversations.createConversation({
bot: { id: botId },
members: [
{ id: recipientId }
],
isGroup: false
});
var activityResponse = await client.conversations.sendToConversation(conversationResponse.id, {
type: 'message',
from: { id: botId },
recipient: { id: recipientId },
text: 'This a message from Bot Connector Client (NodeJS)'
});
console.log('Sent reply with ActivityId:', activityResponse.id);
}
The botID and recipientID is dependent on the channel you use.
Edit : As I misunderstood the intent of the question.
If you want to create a channel, check out
https://github.com/howdyai/botkit/blob/main/packages/docs/core.md
There are officially supported channels with adapters that you can utilize. But if you are looking to connect to a custom app, look at https://github.com/howdyai/botkit/blob/main/packages/docs/reference/web.md#webadapter
for the generic web adapter that you can use to send and receive messages.